Robotics' Wild Kingdom

An engineer looks to nature to make robots that slither through pipes and climb walls

Photos: TOP, Dani Machlis/Ben-Gurion University; Bottom, Tomer Avramovitch and
Avishai Sintov
Animal wright: Israeli robot researcher Amir Shapiro [top] builds snakelike robots (like the one draped around his neck) that can twist like screws. He also makes robots that scale walls [bottom] by releasing
tiny amounts of glue, much as a snail leaves a trail of mucus.

Israeli roboticist Amir Shapiro takes his engineering cues from members of the animal kingdom, though his choices might seem unexpected: snakes and snails. Oh, and cats, too.

In the field of biomimetics-the use of technology to mimic nature--there's a subspecialty that mimics animal locomotion, and several research centers have worked on robots that mimic the undulation of a snake. But Shapiro's team has gone a step further (no pun intended) by combining two concurrent wave motions to create a slithering movement.

"These three-dimensional snakes have two sets of motors that give us two traveling wave motions, in the vertical and horizontal directions," says Shapiro, who heads the robotics lab in the mechanical engineering department at Ben-Gurion University of the Negev, in Beersheba, Israel. "We combined the two perpendicular traveling waves for a screwlike motion that moves the snakebot forward. So it's going forward and around at the same time." This lets it wriggle through small holes and pipes, a trick that could help workers find and rescue people buried under collapsed buildings.

Today the robot is under remote control, but Shapiro plans to make it autonomous. "The idea is to have sensors on the robot--tactile sensors to see where the contact points are, scanning sensors at the head of the snake, a laser scanner, or a camera--and then design adaptive algorithms that can change the motion pattern, the amplitude, phase, and wavelength according to the terrain."

Shapiro, 38, displayed an early affinity for machines. He attended a technical high school, then served as a project engineer designing armored vehicles during his mandatory military service. From there, he went to Technion-Israel Institute of Technology, in Haifa, where he earned bachelor's, master's, and Ph.D. degrees in mechanical engineering. Smitten with robotics because it combines several engineering disciplines, he did a postdoctorate at the Robotics Institute at Carnegie Mellon University, in Pittsburgh, developing his snake robots, before joining the Ben-Gurion faculty.

In 2004, the Israeli military asked him to craft wall-climbing robots for intelligence gathering. His team came up with a tracked robot that scales concrete walls by releasing melted glue, which holds it in place until it can move forward and release more glue. Shapiro's inspiration was the mucus trail that a snail leaves behind. For rough walls, he designed a robot whose four legs carry fishhooks, allowing it to climb like a cat.

He has also equipped a robot with compliant magnetic wheels so that it can clamber on the submerged hulls of cargo ships, perhaps one day replacing the divers who now check for contraband and bombs. "A robot can do it safer, better, easier, and much less expensively," Shapiro says. "A good scanning algorithm can make it very efficient."

His latest project is a robot that shoots arrows attached to strings, which it uses to pull itself along a wall or ceiling. So what animal inspired that?